The objective of this study is to investigate possible causal mechansisms associated with an increased incidence of idiopathic pulmonary hemorrhage in infants in a geographic cluster area in the eastern Cleveland metropolitan area. An investigation by the Centers for Disease Control and Prevention found an association with a toxigenic fungus, Stachybotrys chartarum. Environmental sampling of patient and control homes, done by NIOSH, found this fungus in all but one of the 12 patient homes studied and in 16 of 29 control subject homes. This has been confirmed in 15 of 17 subsequent case infant homes. This project continues with follow-up visits of all affected infants and the inclusion of newly diagnosed patients in order to better describe this apparently new disorder. A prevention program is now in place which inspects newborns' homes in the cluster area. Demonstration studies for risk assessment of toxic mold exposure and the impact of mold on the health of infants and children, especially asthmatic children are underway. These studies include the field testing of two new quantitative assays for environmental toxic mold. Subjects are evaluated clinically before and after home remediation. A related NIEHS RO1 grant is developing an infant rat model of Stachybotrys induced pulmonary hemorrhage with a goal of determining exposure markers which could be used to evaluate level of exposure in the human infants.